Missouri

/mɪˈzʊərɪ/

noun

1.

a state of the central US: consists of rolling prairies in the north, the Ozark Mountains in the south, and part of the Mississippi flood plain in the southeast, with the Mississippi forming the E border; chief US producer of lead and barytes. Capital: Jefferson City. Pop: 5 704 484 (2003 est). Area: 178 699 sq km (68 995 sq miles) Abbreviation Mo, (with zip code) MO

2.

a river in the W and central US, rising in SW Montana: flows north, east, and southeast to join the Mississippi above St Louis; the longest river in North America; chief tributary of the Mississippi. Length: 3970 km (2466 miles)

originally a name for a group of native peoples among Chiwere (Siouan) tribes, from an Algonquian word recorded c.1700, literally "people of the big canoes." The expression I'm from Missouri, you'll have to show me is attested from at least c.1880. Related: Missourian.